Trick plate



June 29, 1954 5 TAF ETAL 2,682,163

TRICK PLATE Filed Nov. 1'7, 1949 Patented June 29, 1954 TRICK PLATE Aaron S. Staif, New York, N. Y., and Richard Lutton Spence, Sao Paulo, Brazil Application November 17, 1949, Serial No. 141,236

12 Claims.

This invention relates to warp knitting machines and more particularly to trick plates for the same.

Heretofore, knitting machines employing trick plates have been limited in their speed of operation and in their number of needles per inch principally by the characteristics of available trick plates. The limiting characteristics were the result of the manner of fabricating the trick plates. Such trick plates were made out of long pieces of heavy steel plate. These pieces were first planed, to give them the proper taper, and thereafter were laterally slotted by milling along their upper edges. The walls separating the slots could only be made as thin as milling procedures could allow, and could not be made with sufficient fineness to avoid limiting the number of needles per inch and the speed of operation, and the conformation and relative positions of the elements were, in general, limited by the manufacturing methods employed. Furthermore, not only was the initial formation of integral trick plates expensive, but, if any of the walls between slots became broken, the repair work was diflicult and expensive.

We have devised a trick plate and method of forming the same which not only eliminates the prior art drawbacks, but provides substantial ad ditional advantages as well. The trick plates of the invention are much cheaper than those previously made, are easy to produce, easy to repair, and are light in weight, but they can nevertheless be made with much finer slot spacing than was heretofore thought possible. Thus greater numbers of needles per inch may be employed and the speed of the operation may be increased. In addition, the parts may be made absolutely uniform in all respects.

It is, accordingly, a general object of this invention to provide improved trick plates for knitting machines.

Another object is to provide such trick plates of a composite construction.

Another object is to facilitate a substantial increase in the number of needles which may be used in knitting machines employing trick plates.

A further object of the invention is to materially facilitate the economical repair and replacement of the tricks in the trick plates of knitting machines.

A still further object of the invention is to provide for higher speed operation of the Racheltype knitting machines.

Further and more detailed objects will appear as the description proceeds with reference to the accompanying drawing, in which Figure 1 is a front elevation of a trick plate element in accordance with a preferred form of the invention, and showing portions of adjoining trick plate elements;

5 Figure 2 is an end elevation of the element of Fi ure 1 as viewed from the right end thereof;

Figure 3 is a rear elevation of the trick plate element structure of Figure 1;

Figure 4 is a side elevation of one of the leaves per see;

Figure 5 is an end elevation on an enlarged scale of so much of a knitting machine as is necessary to show the application of the trick plate of the invention thereto;

15 Figure 6 is a fragmentary enlarged perspective 20 Figure 8 is a view, similar to Figure 6, of another form of the invention.

As has been previously pointed out, the practice followed heretofore in the forming of trick plates was to form them as one continuous steel 25 element extending all the way across the machine. Slots, in which the needles operated, were milled all the way along the element and the minimum thickness to which one was able to mill the material between the slots and defining the same, was the controlling factor in the number of needles per inch that could be employed. Even at prior art speeds, however, and with walls of substantial thickness between slots, the tricks often broke and repairs had to be made by welding. After a certain amount of such repair, however, the whole trick plate had to be discarded and a new one substituted for it.

This invention changes such prior practices, for it provides for the building up of a composite trick plate out of a number of trick plate elements. Separate leaves, suitably formed from a proper steel or other material are secured in a body portion, such as lead or type metal, as by the casting of the material about their lower portions. A plurality of elements so formed is employed to make up a trick plate, by securing the elements individually to a trick plate bar. A preferred form of such an element is shown in Figures 1-3, in which the body of the element is indicated generally at l and the row of leaves forming the slots is indicated generally at 2. Portions of adjoining trick plates identical to the one shown completely are indicated to the right and left of the figure, these additional trick plate elements being identified by reference numerals I-A and l-B.

As shown in Figure 4, each of the leaves has a body portion 3 and a head portion 4. The body portion 3 is provided with some means, such as the perforations and recesses 6, to assist in looking the trick in place in the cast metal. In the embodiment shown, it will be apparent that the leaves 2 may be accurately positioned in a mold by means of their ends 4 and the recesses E, and the body cast around them so that the body metal fills the perforations 5 and locks the structure together. The leaves are preferably made of a good grade of steel, and can, if desired, be made extremely thin compared to the prior art walls which are formed by milling the slots out of a solid bar. The leaves are most simply made by merely stamping out of sheet metal. An actual operating trick plate element made in accordance with the invention may be about the size of the element as depicted in Figures 1-3, the width, as viewed in Figure 1-, being about two inches. The number of leaves employed in the actual element may, and normally will, be much greater than the number illustrated. Furthermore, the actual leaves will normally be much thinner than those illustrated, and need merely to be spaced far enough apart to enable the needles to operate in the slots between them. For producing a fine mesh fabric, a single trick plate element may be provided with, for example, sixty-four leaves and the leaves may be of the approximate thickness of thin razor blade steel, thus forming slots between the leaves about .025 inch wide for accommodating the needles, with the leaves separating the slots being about .005 inch in thickness. Coarser or finer spacing may be utilized as desired within the limitations of the needles and the thread. As will be apparent from the nature of the construction, even thinner leaf material and finer spacing than that specified may be used without sacrificing the needed strength.

As the upper corner I, where the head portion 4 and the body portion 3 of the leaf meet, the leaf is perforated as shown at 8. All of the leaves of a set being identical, it follows that when a set of tricks is properly lined up in an element, as shown in Figures 1 and 3, the perforations 8 are accurately aligned and form a continuous passage for a wire 9, which forms the casting off bar. This wire extends all the way across the machine through the perforations in the leaves of the trick plate elements going to make up the complete trick plate. The wire 9 serves in the same manner as the back edges of the slots in the integral form of trick plate. to engage the thread and cast it off during the down stroke of the needles. The wire 9 can. of course, be drawn out of the trick plate, so that if a leaf of any trick plate element needs repairing, the wire can be withdrawn, the element with the broken leaf removed and a new one substituted in its place.

Turning now to the body I of the trick plate element, the same includes a thick upper receiving portion l0, and a reduced lower securing portion I I. The reduction of the body at the portion H is caused by recessing the body on the side toward which the leaves extend. The recess is bounded by a shoulder l2, and a securing face S3. The receiving portion 10 has a set of leaves secured within it. This is preferably accomplished by holding the tricks, or leaves, in a suitable fixture with their baseportions 3 extending into a mold and pouring the molten lead, type metal, or other suitable cast metal into the mold to encompass the bases 3 of the leaves. The locking of the leaves in place is achieved by the flowing of the metal through the perforations 5, so that regardless of whether the metal completely fills the spaces between the side faces of the bases 3 at all points, the whole structure will be locked together. Inasmuch as the leaves extend a substantial distance above the top of the receiving portion I0, as shown at It, any inaccuracy in the top edge of the cast metal will not interfere with the operation.

The securing portion ll of each element is designed to enable the element to be accurately and effectively clamped in place on a trick plate bar 15, as shown in Figure 5. Obviously, the formation of the trick plate bar, and the mated form of the securing portion of the trick elements can. be varied from that here illustrated. The particular holding arrangement shown here is, however, a simple and effective one. The shoulder l2 engages the upper edge 16 of the trick plate bar and the face [3 lies against the outer surface H of that bar while the bottom iii of the element lies against the laterally extending surface IS. The securing portion H is perforated at 20 to receive a bolt, or other suitable fastening, 2l. The head of the bolt engages the outer surface of the portion H while its shank is secured in the body of the bar, as shown at 22 in Figure 5. Thus, the trick plate element is accurately located with respect to the trick plate bar and is securely held in place thereon. This same locating and securing feature extends through the length of the trick plate bar, so that a plurality of identical trick elements secured thereon will provide a fully effective and greatly improved trick plate. Should one of the leaves break, it is merely necessary to remove the wire 9 as far as the element carrying the broken leaf, remove that element from the bar, replace it with a good one and replace the Wire.

The manner in which the needles are related to the trick plate is illustrated in Figure 5. Here, a conventional latch type needle 23, having a latch 24, and needle hook 25 is shown in operative relationship with respect to the trick plate. The needles here, like the leaves 2, may likewise be suitably secured in a cast base, generally indicated at 25'. The base 25 is provided with a seating shoulder 26, a seating surface 21, and a bottom edge 28, all of which are accurately related to, and secured against the respective complementary surfaces 25, 30, and 3 l, of a needle bar 32. The needle blocks 25 are thinner than the trick plate elements I and, proportionately, the shanks of the needles extend for a shorter distance within the block, than their operating ends project above it. The needle blocks will generally be narrower than the trick plate elements, but by employing a suitable number of them they will fill the space across the machine, the same as is done with the trick plate elements just described.

A modified form of leaf is shown in Figures 6 and 7. Here, the body I of the trick block need be no different from that of Figure 1, nor do the bases 3 of the leaves, need to be any different. Instead of the perforation 8, however, each of the leaves in this modification is formed with a dovetail groove 32' at the corner between the base 3 and the head 4. This dovetail groove has inwardly extending locking portions 33 and 34 to engage and interlock with the mated portions of a bar 35. Since the dovetailed grooves 32 of each leaf are accurately formed, and accurately aligned when the leaves are held in the body I, the bar 35 can be slid into place from the end of the machine and takes the place of the wire 9 previously described. The bar 35 also has its outer surface curved at 36 in order to impart a radius to the corner of the leaves in which it seats. Thus, any likelihood of a rough surface, or one which might catch on anything is eliminated. Furthermore, the bar 35 will provide a more extensive corner surface than the wire 9 with the attendant advantages thereof.

The essential operating elements of a trick plate consist in the slots in which the needles operate and which are defined, according to the invention, by the leaves 2, the casting off bar defined by either of the elements 9. or 35 and in the surfaces at the rearward upper corner of the trick plate and below the same over which the finished fabric passes. As will be apparent, the invention permits practically any desired relative locations or dimensions for the essential parts and is thus adapted to a wide variety of appli cations. For example, the depth of the slots for the needles may be practically anything desired, whereas in the prior art constructions this depth is limited by the strength of the dividing wall left after the milling operation. Similarly, the casting off bar 9 or 35 may be of any desired cross-section, whereas in the prior art the contour and location of this element is limited by the practicality of milling the bottoms of the needle slots. In particular, the actual edge which engages the thread and casts it off the needle, the upper surface of the bar over which the threads pass into the fabric being formed and the rearward surface of the bar over which they may slide as the fabric is drawn ofi, may all be located for the best performance. Such results'are clearly unobtainable in the integral milled trick plates of the prior art. Moreover, the various parts may be made of practically any desired material so as to adapt them to the functions to be performed, whereas in the integral trick plate all parts must be of the same material.

Another alternative trick plate element is shown in Figure 8. Here the necessity of perforating or grooving the trick leaves is eliminated. Instead, these leaves 31 have their back portions 38 cut away somewhat, in order to receive a plate 39 providing the casting off edge for holding up the thread. The plate 39 has a curved upper edge 40, which curve extends into alignment with the upper edge of the heads of the tricks.

Both the plate 39 and the bases of the leaves 31 are secured in the body 42 of the trick plate. The securing of the bases of the leaves follows the practice heretofore described, while the plate, as shown in dotted lines 43, merely has a portion extending suficiently within the castmetal of the body 42 to hold it properly and. rigidly in place. This construction in appearance more closely simulates the integral arrangement of the prior art than either of the previous forms, but it will be clear that similar advantages to those obtained in the earlier described embodiments may be also obtained with this construction.

Inasmuch as other manners of practicing this invention might well suggest themselves to one skilled in the art, it is to be kept in mind that the embodiments of the invention heretofore described are submitted for illustrative, and not limiting, purposes. While lead and type metal have been mentioned as the materials suitable for casting of trick blocks, it is, of course, to be understood that any other suitable metal may be employed. Furthermore, no particular form of perforation or depression in the leaves for reception of the cast material is believed necessary, the ones disclosed herein being effective, but also being subject to replacement by other elfective formations. Finally, the material from which leaves are to be constructed may be anything which would be selected by one skilled in the art to satisfy the conditions imposed on such a machine part.

The trick plate of the invention, in whichever form made, is preferably made concave on its rear surface just below the stitch throwing off edge or bar. Thus in the embodiment of Figures 1 to 5, a concavity 56 is formed in each of the leaves 2 just below the wire 9 and a similar concavity 5| is formed in each of the leaves in the embodiment of Figures 6 and 7 just below the bar 35, which in this case forms the stitch throwing off edge. In the embodiment of Figure 8, in which the throwing off edge is formed on a solid plate extending upwardly of the backs of the leaves, a groove 52 is provided in this plate. The purpose of the concavity at this location is the same in all embodiments and will be readily understood from Figure 5. In that figure, the line 53 indicates the general course of the knitted fabric which passes downwardly over the body of the trick plate as formed. For detecting dropped stitches and stopping the machine as quickly as possible, a row of loosely mounted metallic elements, such as cotter pins 54, may be slidably supported on a member such as the plate 55, these cotter pins being retained in place by means of a wire 56 extending the width of the trick plate. As will be apparent, a gap in the mesh will permit a cotter pin 54 to slide downwardly and toward the trick plate, making contact with one of the leaves 2. Suitable electrical connections to the trick plate and to the cotter pin wire 56 will thus permit detection of contact between these members so as to actuate an alarm or stop the machine automatically. Such a stop motion device forms no part of the present invention in itself. However, by forming the back of the trick plate with a concavity at the location shown, the action of an electrical detector may be improved.

Where very fine thread is being knitted and particularly where the surfaces of the trick plate under the fabric as it emerges consists of a number of these leaves as in the embodiment of Figures l to 7, it willbe found that electrical connections may be established occasionally even if a perfect mesh is being produced. By forming the trick plate with a concavity so that the fabric passes over the same a small distance therefrom, undesired contact between the cotters 54 and the trick plate may be prevented. Should a stitch be missing. however, the cotter will be able to slide down sufliciently to make contact with the trick plate. While the concavity is more necessary in the embodiment of earlier figures, it may also be provided as shown in Figure 8 where the back of the trick plate is solid, if desired.

What is claimed is:

1. In a trick plate construction for knitting machines, a trick plate element comprisin a series of separate leaves defining a plurality of open needle slots and forming partition walls separating the same, and a body portion supporting the said leaves, the body portion having a generally flat face and the leaves extending upwardly and transversely of the said face beyond the plane thereof, the portions so extending being free and disconnected from each other.

2. A trick plate element according to claim 1, in which the body portion comprises a casting in which the leaves are imbedded.

3. A trick plate element according to claim 1, comprising also a member extending along the series of leaves for forming a casting off bar.

4. A trick plate element according to claim 3, in which the said member forming the casting off bar comprises a wire and the leaves have apertures receiving and holding the same.

5. A trick plate element according to claim 1, in which the leaves are formed to receive a common member extending across them and forming a casting off bar.

6. A trick plate comprising a plurality of elements according to claim 5, arranged in alignment together with a casting 011 bar common to all elements.

7. A trick plate element according to claim 5, in which the partition walls are perforated to receive a wire forming the casting oiT bar.

8. A trick plate comprising a plurality of ele ments according to claim '7, arranged in alignment together with a common wire passing through the perforations thereof to form the casting off bar.

9. A trick plate element comprising a body portion and a plurality of partition walls extending upwardly and laterally to one side to form open needle slots, and a casting oif bar extending across the partition walls and spaced above the body portion.

10. A trick plate for knitting machines comprising a body portion having a generally flat face and an aligned series of partition walls extending outwardly beyond the plane of the said face defining and separating open needle slots for accommodating needles reciprocating in parallelism to the said face, the trick plate rearwardly of the needle slots being concave so as to permit the fabric as formed to be drawncfi chordwise and spaced from the trick plate over the concavity.

111A trick plate construction for knitting machines comprising a body portion having a generally flat face, a plurality of leaves supported thereby extending outwardly beyond the plane of the said face anddeflning and separating an aligned series of open needle slots for accommodating needles reciprocating in parallelism to the said face, the trick plate rearwardly of the slots being concave so as to permit the fabric as formed to be drawn off chordwise and spaced from the trick plate over the concavity.

. 12. A leaf for use in a knitting machine trick plate, comprising a shank for holding the same in a supporting member and a head extending laterally from one edge of the shank, the opposite edge of the shank being formed with a concavity, whereby fabric may be drawn off an aligned series of such leaves, when supported to form a trick plate, chordwise thereof and spaced from the leaves over their concavities.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 8,773 Henson Mar. 2, 1852 1,116,444 Kramer Nov. 10, 1914 1,436,529 Preston Nov. 21, 1922 1,939,092 Welffens Dec. 12, 1933 1,981,513 Kinsella et al. Nov. 20, 1934 2,014,529 Kinsella et al. Sept. 17, 1935 2,155,145 Morton et al. Apr. 18, 1939 2,195,401 Bahner -1 Apr. 2, 1940 2,259,655 Morton Oct. 21, 1941 FOREIGN PATENTS Number Country Date 19,315 Great Britain of 1914 481,120 Great Britain Mar. 4, 1938 

